So, a couple of months ago I went to his house to try to fire her up, first start after rebuild. The engine was rebuilt by a known portuguese builder who wins races and knows his stuff. This to me, at this point, doesn't have much significance since mine was at first also built by someone reputedly good and was destroyed after 500 metres running due to several parts missing inside it
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The first thing I did was trying to rotate it. For starters, it was stuck. With one wheel in the air, both of us eventually got it loose. It only had a bit of oil (assembly oil?) which we took off and replaced with new oil.
Then rechecked the cylinder head torque (40lbft)... half of the nuts were loose. Rocker gear (new 1.5 rockers) had these tiny spacers (half the size they should be) which were doing nothing, completely loose. I had to get the springs from the old set. Valve clearances were also wrong.
Next... dizzy advance totally stuck. We refurbished the dizzy (oh... and the starter) and I put the dizzy with a static advance of 7/8º BTDC. Then the solenoid didn't work (new Lucas one), the old one did. We got good oil pressure but the engine felt slow rotating, like everything was tight. Mine is a 1275 with tight tolerances and spins much, much freely. The battery was fully charged and when that died we went to get another, more powerful, from a diesel car which gave the same intensity spinning the engine. It really feels tight, also by hand, but is constantly tight. No grabbing spots. At the speed the starter rotates it, it should present no problem to start.
Fuel: the carbs were refurbished by me and I know they're good. No air leaks in the manifolds. Plugs with fuel after a few times rotating the motor, so there's definetely fuel coming into the chambers. Cleaned spark plugs several times.
Spark: I'm 100% sure that when the firing stroke was occurring in each cylinder, the dizzy rotor/lead was pointing at that cylinder. Checked and rechecked that several times. All 4 plugs had sparks, they're not very strong but they're not weak either. 2 coils tried, 2 sets of points, 2 condensers, 2 dizzy caps + leads, sparks are new BP6ES gapped at 0.8mm. 2 earth straps well fitted. The strenght of the spark was always the same.
Compression: after a bit insisting to fire up, it eventually back fires through the exhaust, so there's compression accumulating. I'm assuming the pistons have rings
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After this, it was late and I had to return (150km each way), but promised to return again some day to fire her up. I should go there next week or so. Since it's a long distance, I want to go with a plan to at least diagnose the problem. I'd like to give him (and know myself) some answers.
I need to check if the timing gears aren't 1 tooth off. How can I do that without taking anything appart? If we split the overlap (rockers rocking) on the 1st cylinder, the flywheel should present exactly the TDC mark, right? If the timing was 1 tooth off, should I have noticed it was not right when setting the ignition (how much impact 1 tooth off has)? Do you have any other ideas for me to check out? Any thoughts?
- We have oil pressure
- We have petrol
- We have spark
- We have compression
- Ignition timing seems OK
- Does not fire up, never even once gave a heart beat